The present invention relates generally to the field of automobile safety. Specifically, the present invention is directed to systems and methods for providing a sealed vehicle sensor printed circuit board assembly and a sealed connector interface. The printed circuit board assembly and the connector interface are both provided within an overmolded housing.
Automobile restraint systems such as airbags, tension seatbelts, etc., employ sensors in various places within the automobile to detect, for example, crash events in which the airbags or other safety equipment should be deployed. Generally speaking, a sensor is a device which senses the state of an environment. For example, a sensor can sense the surrounding temperature or pressure. With respect to automobile restraint systems, the crash sensors typically sense the automobile's acceleration to detect the crash event, although other methods for detecting the crash event can be used.
As illustrated in FIGS. 1 and 2, a typical crash sensor assembly generally includes a housing 1 of some type for protective purposes, a printed circuit board assembly 2 having sensor electronics 3 residing thereon, a mounting assembly 4 used to fasten the crash sensor assembly to the automobile body and a connector interface 5 to make electrical connection to the automobile electrical system. The printed circuit board assembly 2 is typically sealed inside the housing 1 which is made of a polybutylene terephthalate (PBT) polymer material. The PBT housing 1 also includes an integral male connector 6 with a shroud. The male connector 6 and the shroud are designed in such a way to be sealed permanently from the environment to protect the electrical interconnections. A female connector of the automobile electrical system (not shown in the drawing) typically has special seals that mate against the inside of the connector shroud and form an environmental barrier. The PBT polymer material is chosen because it is an industry standard for connectors.
After the printed circuit board assembly 2 is placed within the PBT housing 1 of the crash sensor assembly, a potting material, a sealant or a welded cover is typically placed over the opening of the PBT housing 1 to seal the contents from the ambient environment.
One drawback with the conventional crash sensor assembly is that the PBT polymer material is not particularly suited for the protection of electronic components. For example, the PBT polymer material is not particularly suited for protecting the electronic components against thermal stresses that occur within the closed area accommodating the printed circuit board assembly 2. Another drawback with the conventional crash sensor assembly is the additional cost of the potting material, sealant or welded cover, as well as the additional manufacturing step required for adding these features which increases the overall cost of the crash sensor assembly.
In view of the foregoing, there exists various needs in the art. One such need is for a crash sensor assembly that is simpler in design and still protects the electronic components against thermal stresses and the ambient environment. Another need is for a crash sensor assembly that can be manufactured at a substantially lower cost without reducing the functionality of the assembly.